Process for the production of alkali metal phytates



Patented Feb. 14, 1950 moors-sroman:*rnonpc iroapraiix m METAL PHYTATES Neal Oak Bark, Ill;,--ass ignorto ProductsRefining Gompany; New- Yorlt -Ni-y a corporation of Newdersey Nii DiaWinQ-T'fi ApplicatidnhfiirhTifil die sense-No. 735,240

4 cisims. (Cl. ecu-4" to" This invention' relates to -the preparation ot alkali metal phytates. 1 More particularly, it re lates to the? preparation of= such-phytates-iroin magnesium phytate. 7

An object of the 'presentdnventionds to provide-a simple and effective method-ior thepreparation of. alkali metal iphytate directly; from magnesium ;phytate. l- The magnesium phytate which is satisfactory*forthe purpose ot the present. invention is obtained as a precipitate from the) treatment of corn steep liquor withmage nesium hydroxide... Thus, when cornsteep'liquor is'neutralizedwi-thi magnesium hydroxide the pre cipitates that form are crude salts :o f -ph-ytic acid consisting mainly of. magneslumphytate-hut a small amount-'ofl calcium -may the contained thereinm.

Heretofore'. sodium phytate; -for examplelhas been prepared-from metal ahytates,such-ascalcium phytaten. by: .first converting; the-calcium phytateto iron phytate. eThis is'eiifectedbye-dis solving the: calcium phytate in hydrochloric acid ofcproper concentration and adding .tosuchsolution a solution of. ferric chloridein hydrochloric acid. Thereupon, ironphytate precipitatesi- The iron. phytate, after being separated. is suspended inlwaterand'to this suspension-is added a soluqtion ofsodium hydroxide-, whereupon insoluble ferric .-hydroxide is formedand remains-in suspension in the alkaline solution; This --is separatedand the sodium :phytate'is recovered f-rom the filtrate by adding alcohol 1 thereto. This causes the sodium phytate to separateas -a heavy sirupinlthe bottom layer. If the sirup is cooled somewhat below room temperature, or is allowed to stand for sometime at rooni temfierature, crystals of sodium phytate may form thereupon. .7

M'yinventionrepres'ents' an improvement'cver such complicated procedure, and-uy'means 6f lnvention,-:alkalii metsnphytate: mayme' prepared directlyirom magnesium phytate.

The; process of the presi'it'ifivention com-prises reacting magnesium phytatewi'tli a solutidri't'if alkali metal hydroxide, and recovering the alkali metal phytate; the alkali metal hydroxide being present in a ratio which will provide at least 2 mols of alkali metal hydroxide for each atom of phytic acid phosphorus present in the phytate.

The magnesium phytate and the alkali metal hydroxide and the water necessary to provide the alkali metal hydroxide solution may be mixed in any order.

The reaction is exothermic and begins at room temperature. It is preferable to mix the reactants at such dilution of alkali metal hydroxide that 2 the: temperatureof the *reaction mass does "not rise aboutabout -120--F.- IP-the temperature o f the reaction mass rises above 120 ;F'. ;:;it is dim} cult-to filter the magnesium hydroxidegformed during the reaction at-- the higher temperature;

hydroxide is separated, as by-flltratione from theremaining-.iiquor which contains the *desired; alika-limetal phytate in solution. The '-magnesium hydroxide cake is then washed. Alcoholis-then added---to--the-liquorinchidingthe --washing s in amount;-usually'about l'gl pereentto about 25 pore cent of volume, sui iicient to produce the maxi- .malsepa-ration ofalkali metal phytateas a sirup' The -alcohol -requ-irement is higher for potassi-um phytate-than fon sodiuimphytatg ;The mixture is therr aliowed tdstandand within -a shorttime; the liquid willseparate into two layersethe heavy alkalt metahphytateflayer being onthe bottom; The upper layer is drawn oif-and savedforthe recovery of-alcohcl which-may beqused-ina sub sequent-reaction: The heavy alkali metalphytate layer,- which -is -sirupy= in nature; maybe used-directly or *i a ew-b ied bypassin ever heated rolls-or it may be allowedv to crystallize andthe-alkali metai sphytate crystalsrecovered in conventional manner. 7 g

If it is desired to--;obtai-n alkali metal phytate in its crystalline; form; rathertharras a :siru'p; thespecifio-gravity of'the solution containing the alkali -metal phytatex-afterremoval of magnesium hydroxide,- may beadjusted-'= by concentration to a; point :at which erystals may beginto form-when the=s91ution-coolse- The additiozrrof "not more than L0=-percent of-its volume of ethyl alcdhol'to such a solution may cause separation of a larger crop of crystals of alkali metal phytate without causing the separation of two liquid phases.

The alkali metal phytate thus obtained may contain traces of free alkali metal hydroxide which changes to alkali metal carbonate on contact with air. If a product of" greater purity is desired, the alkali metal phytate may be redissolved in water, alcohol added thereto and the resultant mixture treated, as above described.

Among the alcohols which may be employed for recovering alkali metal phytate, in accordance with the present invention, are methyl alcohol, ethyl alcohol and isopropyl alcohol.

Any grade of reactants may be used, the commercial grades being quite satisfactory.

Any equipment which is resistant to alkali is suitable for purposes of the present invention.

The following examples which are intended as informative and typical only and not in a limititing sense will further illustrate the invention,- which is intended to be limited only in accordlance with the scope of the appended claims. Where reference is made to amounts of phytic acid phosphorus, determination thereof was carried out according to the method of Heubner and Stadler, Biochem. Z., 64, 422-37.

Example I.-Commercial magnesium phytate was prepared by adding magnesium hydroxide to corn steep liquor in amount to adjust the pH value thereof to 6.5. The precipitate which formed was separated, washed, and dried in conventional manner. To 500 grams of such magnesium phytate (containing 83.5 g. of phytic acid phosphorus) slurried in 1200 ml. of water was added with stirring a solution made by dissolving 230 g. of sodium hydroxide in 800 ml. of water. The temperature of the reactants was about 70 F. and the temperature of the reaction mass rose to about 85 F. during the reaction. The mixture was allowed to stand for 2 hours. The solids were then separated by filtration. Determination of the phytic acid phosphorus in an aliquot of the filtrate showed 96 percent conversion of the magnesium phytate to sodium phytate. To the filtrate, one-fifth its volume of isopropyl alcohol was added and mixed in thoroughly. A heavy sirup of sodium phytate separated, which set up to a mass of crystalline sodium phytate on standing overnight. 2

Example Z.-Twenty liters of magnesium phytate slurry containing 250 g. of phytic acid phosphorus was treated with 3.5 l. of a solution containing 640 g. of sodium hydroxide, the magnesiumphytate being prepared according to the method described in Example 1. The reactants were mixed at room temperature and during the reaction the temperature of the reaction mass rose about F. After standing overnight the solids were separated by filtration. Titration of an aliquot of the filtrate showed 97 percent conversion ofthe magnesium phytate to sodium phytate. Twenty peroentof its volume of isopropyl alcohol was 'mixed with the filtrate and the heavy layer of. sodium phytate sirup was drawn off and dried by passing overheated rolls to an almost white. flaky powder.

Example 3.,Sixty-four grams of potassium hydroxide was dissolved in 700 ml. of water and 100 g. of magnesium phytate. prepared according to the method described in Example 1, was slurried into the resulting solution. The temperature of the reaction mass'rose to about 85 F. After standing 1 hour, the solution was filtered and the cakewas washed witlihot water until the volume of filtrate and washings amounted to 1 liter. Determination of phytic acid phosphorus in an aliquot of this solution showed 100 percent conversion of the phytic acid phosphorus oi the magnesium phytate to soluble potassium phytate. Addition of ethyl alcohol to the filtrate caused separation of the potassium phytate as a thick sirup in a manner analogous to the behavior of sodium phytate solutions subjected to such treatment.

I claim:

1. The process which comprises mixing a magnesium phytate precipitate obtained from the treatment of corn steep liquor with magnesium hydroxide, with a highly diluted aqueous solution of an alkali metal hydroxide to effect a chemical reaction between said magnesium phytate and said alkali metal hydroxide, the proportions of said reactants being at least 2 mols of alkali metal hydroxide for each atom of phytic acid phosphorus present in said magnesium phytate precipitate, the temperature during the reaction being maintained at less than about 120 F., and the time during which the reaction is efiected being at least about one hour.

2. The process according to claim 1 wherein the magnesium hydroxide formed during the reaction is separated and the alkali metal phytate is recovered from the remaining liquor by adding thereto an alcohol selected from the group consisting of methyl alcohol. ethyl alcohol and isopropyl alcohol in an amount of from 10 to 25 per cent by volume of the liquor to which said alcohol is added.

3. The process which comprises mixing a slurry in 1200 ml. of water of 500 grams of a magnesium phytate precipitate containing 83.5 grams of phytic acid phosphorus and obtained by the treatment of corn steep liquor with magnesium hydroxide, with a solution of 230 grams of sodium hydroxide in 800 m1. of water, maintaining the temperature during the reaction at between F. and F., and allowing the mixture to stand for about 2 hours.

4. The process which comprises mixing grams of a magnesium phytate precipitate containing 16.? grams of phytic acid phosphorus and obtained by the treatment of corn steep liquor with magnesium hydroxide, with a solution of 64 grams of potassium hydroxide in 700 ml. of water, maintaining the temperature of the reaction at not in excess of 85 F., and allowing the mixture to stand for 1 hour.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,644,246 Gains et al. Oct. 4. 1927 

1. THE PROCESS WHICH COMPRISES MIXING A MAGNESIUM PHYTATE PRECIPITATE OBTAINED FROM THE TREATMENT OF CORN STEEP LIQUOR WITH MAGNESIUM HYDROXIDE, WITH A HIGHLY DILUTED AQUEOUS SOLUTION OF AN ALKALI METAL HYDROXIDE TO EFFECT A CHEMICAL REACTION BETWEEN SAID MAGNESIUM PHYTATE AND SAID ALKALI METAL HYDROXIDE, THE PROPORTIONS OF SAID REACTANTS BEING AT LEAST 2 MOLS OF ALKALI METAL HYDROXIDE FOR EACH ATOM OF PHYTIC ACID PHOSPHORUS PRESENT IN SAID MAGNESIUM PHYTATE PRECIPITATE, THE TEMPERATURE DURING THE REACTION BEING MAINTAINED AT LESS THAN ABOUT 120*F., AND THE TIME DURING WHICH THE REACTION IS EFFECTED BEING AT LEAST ABOUT ONE HOUR. 